Phil Everly — one-half of the harmonious rock vocal duo that influenced the Beatles, the Beach Boys, Simon and Garfunkel, and countless other musicians — died Friday in Burbank, Calif. of complications from chronic obstructive pulmonary disease. He was 74.

“We are absolutely heartbroken,” his wife, Patti Everly, told the LA Times, noting that the disease was the result of a lifetime of cigarette smoking. “He fought long and hard.”

“I was listening to one of my favorite songs that Phil wrote and had an extreme emotional moment just before I got the news of his passing,” Phil’s brother, Don Everly, wrote in a statement to The Associated Press on Saturday morning. “I took that as a special spiritual message from Phil saying goodbye. Our love was and will always be deeper than any earthly differences we might have had.”

“I loved my brother very much,” the 76-year-old wrote. “I always thought I’d be the one to go first. … The world might be mourning an Everly Brother, but I’m mourning my brother Phil Everly.”

Phil and Don Everly

Phil Everly was born in Chicago on January 19, 1939. His parents, Ike and Margaret Everly, were well-known country musicians. At the age of six, Phil began singing on the family’s weekly radio show with his eight-year-old brother Don. By their teens they had signed a recording contract.

The Everly Brothers became one of the biggest rock and country acts of the 1950s and early 1960s, landing 35 Top 100 songs — more than any other vocal duo.

“Perhaps even more powerfully than Elvis Presley, the Everly Brothers melded country with the emerging sound of Fifties rock & roll,” Rolling Stone magazine said in placing the brothers at No. 33 on its list of the “100 Greatest Artists.”

John Lennon and Paul McCartney called themselves the Foreverly Brothers early in their careers, and Art Garfunkel told Rolling Stone that the brothers’ harmonizing had taught him that “every syllable can shine.”

The Everly Brothers breakthrough hit was “Bye Bye Love” in 1957. It rose to No. 2 on the U.S. charts. Their first No. 1 hit (also released in 1957) was “Wake Up Little Susie.”

In 1973, the brothers had an infamous onstage breakup during a concert at Knott’s Berry Farm amusement park in Buena Park, California.

“Phil Everly threw his guitar down and stormed off the stage during a performance of ‘Cathy’s Clown,’ leaving Don to tell the stunned audience the group was finished,” Rolling Stone reported.

After the split, Phil and Don Everly pursued solo careers, and in September 1983, after a decade of solo projects, they reunited for a show at London’s Royal Albert Hall.

Phil told Time magazine that the decade-long estrangement may have affected their professional relationship, but their strong brotherhood remained intact.

“Don and I are infamous for our split, but we’re closer than most brothers,” Phil said. “Harmony singing requires that you enlarge yourself, not use any kind of suppression. Harmony is the ultimate love.”

In addition to his wife, Everly is survived by sons Jason and Chris, two granddaughters, his brother, Don, and their mother, Margaret.